The present invention relates generally to optical systems, and more particularly, to a system and method for converting and displaying image data in real time in a photolithography system.
Digital systems, such as those used in maskless photolithographic processing, require image data to be processed and projected onto a subject. The amount of image data that must be processed is generally relatively large, and increases when higher resolutions are desired. Higher resolution may be desirable for a number of reasons. For example, a line may have a minimum width when projected at a certain resolution. This minimum width may be undesirable, for instance, because it limits the number of lines which may be projected onto the subject. Using a higher resolution may allow the line to be projected using a smaller minimum width, and so more lines may be projected onto the subject. In photolithography, the subject may be a substrate and the projected image may be a mask. Therefore, a higher resolution enables a more detailed mask to be projected onto the substrate without altering the size of the substrate.
A two dimensional image, such as may represent a photolithography mask, may be thought of as lying in a coordinate system having two axes. One common example of such a coordinate system utilizes an x axis and a y axis. An image is generally displayed through or from a projection device, such as a pixel panel, so that the edges of the image are aligned with the x and y axes of the pixel panel. In other words, the top and bottom edges of the image may be parallel to the x axis and perpendicular to the y axis, while the left and right edges may be parallel to the y axis and perpendicular to the x axis. This allows relatively simple techniques to be used to design and store the image in the computer system, since it is can be stored in a memory array using techniques well known in the art and projected by the pixel panel.
However, in applications where the image is projected onto a subject, the resolution of the projected image is constrained by the fact that it is limited to the resolution available on the pixel panel. In applications such as maskless photolithography, this results in a maximum resolution which is limited by the resolution of the original image, the resolution of the pixel panel, the transfer rate of the system, the available storage capacity, and similar factors.
Therefore, certain improvements are needed in converting and displaying image data. For example, it is desirable to convert an image in real time for projection upon a subject. It is also desirable to manipulate the image in order to project the image as desired. It is also desirable to use minimal storage space, to transfer data as efficiently as possible, to provide high light energy efficiency, to provide high productivity and resolution, and to be more flexible and reliable.